Written by Greg Arnold, DC, CSCS. Curing meats is used for preservation but usually uses nitrates which are chemicals that have a cancer risk. In an animal study those supplemented with calcium had 67% lower levels of a material linked to cell damage and 52% less of precancerous lessions. Vitamin E had 48% lower levels of precancerous lesions.
Colorectal cancer is the third most common type of cancer in the United States (1), claiming more than 55,000 Americans and 140,000 new cases each year (2). It is estimated that one in four Americans (80 to 90 million) are considered at risk because of age or other factors. One of these risk factors is meat consumption (3), especially cured meats (4). The World Cancer Research Fund panel stated that “the evidence that red meat and processed meat are a cause of colorectal cancer is convincing” and recommended to “limit the intake of red meat and avoid processed meat” (5).
Now a new study (6) suggests that vitamin E and calcium may help offset the harmful effects of consuming cured meats. In the first part of the 2-part study, 36 rats were fed an experimental cured meat diet for 14 days (shown to cause colorectal cancer in rats) (7). The meats were then injected with calcium carbonate (1.5 g/100 grams meat) and vitamin E in the form of alpha-tocopherol (0.05% of the diet) or nothing (control) for 14 days. At the end of the study, colon tissue samples were obtained from the rats.
In the second part of the study, 17 healthy men between the ages of 40 and 75 with no history or clinical symptom of colonic disease, no history of family colon cancer, and normal standard blood tests were divided into one of 3 groups:
- Cured meat (DCNO -dark cooked meat with nitrite, oxidized) – control group)
- Cured meat taken with 500 milligrams of calcium carbonate per day
- Cured meat enriched with vitamin E as in the rat protocol (alpha-tocopherol 0.05%)
Each group consumed 4 slices of meat per day, totaling 180 grams. This was done for 4 days, followed by a “washout” period for 3 days, then put in another group for 4 days, then another 3-day washout, then the third group for 4 days. Urine and stool samples were collected throughout the study periods.
In the human study, levels of cell damage in the stool samples (called TBARS – thiobarbituric acid reactive substances) were 42% lower in the calcium group (24.5 vs. 42 micromoles/Liter, p < 0.017) and 27.4% lower in the vitamin E group (30.5 vs. 42 micromoles/L, p < 0.017) compared to the control group.
When they looked at the levels of a ATNC (apparent total N-nitroso compound (4)), a compound thought to contribute to the onset of colorectal cancer (7), the calcium group had 53% lower levels of ATNC compared to control group (48 vs. 59 nanomoles/Liter, p < 0.017) with no significant difference found in the vitamin E group.
In the rat study, those in the calcium group had 67.2% lower levels of TBARS compared to the control group (23 vs. 70 micromoles/Liter, p < 0.05) with no significant reduction in the vitamin E group. What’s more, those in the calcium group had 51.9% lower levels of a precancerous lesion in the colon called MDF (mucin-depleted foci) compared to the control group (1.3 vs. 2.7 foci, p < 0.05) and 48.2% lower levels in the vitamin E group versus the control group (1.4 vs. 2.7 foci, p < 0.05).
For the researchers, “Data suggest that the addition of calcium carbonate to the diet or alpha-tocopherol to cured meat may reduce colorectal cancer risk associated with cured-meat intake.”
Source: Pierre, Fabrice HF, et al. “Calcium and α-tocopherol suppress cured-meat promotion of chemically induced colon carcinogenesis in rats and reduce associated biomarkers in human volunteers.” The American journal of clinical nutrition 98.5 (2013): 1255-1262.
© 2013 American Society for Nutrition
Posted November 19, 2013.
Greg Arnold is a Chiropractic Physician practicing in Hauppauge, NY. You can contact Dr. Arnold directly by emailing him at PitchingDoc@msn.com or visiting his web site at www.PitchingDoc.com
References:
- Siegel R, Naishadham D, Jemal A. Cancer statistics, 2012. CA Cancer J Clin 2012;62:10–29.
- “Colorectal Cancer Fact Sheet” posted on the Foundation for Digestive Health and Nutrition Website
- Chan DS, Lau R, Aune D, Vieira R, Greenwood DC, Kampman E, Norat T. Red and processed meat and colorectal cancer incidence: meta-analysis of prospective studies. PLoS ONE 2011;6:e20456.
- Bastide NM, Pierre FH, Corpet DE. Heme iron from meat and risk of colorectal cancer: a meta-analysis and a review of the mechanisms involved. Cancer Prev Res (Phila) 2011;4:177–84.
- Geissler C, Singh M. Iron, meat and health. Nutrients 2011;3:283–316.
- Pierre FHF. Calcium and a-tocopherol suppress cured-meat promotion of chemically induced colon carcinogenesis in rats and reduce associated biomarkers in human volunteers. Am J Clin Nutr 2013;98:1255–62
- Santarelli RL, Vendeuvre JL, Naud N, Tache´ S, Gue´raud F, Viau M, Genot C, Corpet DE, Pierre FH. Meat processing and colon carcinogenesis: cooked, nitrite-treated, and oxidized high-heme cured meat promotes mucin-depleted foci in rats. Cancer Prev Res (Phila) 2010;3: 852–64.
